Recoilless gun having radially movable breech sectors



cw. MUSSER 2,874,614

RECOILLESS sun HAVING RADIALLY MOVABLE BREECH SECTORS Original Filed Feb. 11.1952 2 Sheets-Sheet 1 Feb. 24, 1959 INVENTOR c WALTON Mus'sER 7.7% mega.

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2 Sheets-Sheet 2 Original Fi led Feb; 11, 1952 I 5S 1 i? t wdE IN V EN TOR. C WALTON MUSS ER RECOILLESS HAVING RADIALLY MOVABLE BREECH SECTORS C Walton Musser, Beverly, Mass., assignor to the United States of America as represented by the Secretary of the Army 1 2,874,614 Patented Feb. 24, 1959 As evident in Figs. 1 and 5, chamber 19 is joined to barrel 18; the barrels externally threaded rear end 25 Original application February 11, 1952, Serial No.

271,056, now Patent No. 2,791,961, dated May 14, 1957. Divided and this application January 14, 1957, Serial No. 634,128 a 3 Claims. (Cl. 891.7) (Granted under Title 35, U. S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.

This is a divisional application originating from U. S. patent application Serial No. 271,056 filed February 11, 1952, for Recoilless Type Ammunition Having Self-Contained Venturi, in my name and issued May 14, 1957 as Patent 2,791,961.

The invention herein relates to recoilless guns and has for a prime object the provision of such a gun having a longer useful life than has heretofore been possible. This object is accomplished by constructing the gun so as to include a plurality of radially movable sectors, which sectors define a venturi opening and encircle a similarly shaped portion of the ammunition round preferably used in the gun so that, when the ammunition is fired, most of the gas generated is conducted to the exterior of the gun without coming into direct contact with the gun.

The following description and the accompanying drawings pertain to the construction and operation of one embodiment of the invention.

In the drawings:

Fig. 1 is a side view of the gun, partly in section and partly broken away;

Fig. 2 is a view taken along line 2-2 of Fig. 1 and looking in the direction there indicated;

Fig. 3 is a representative portion of a cross section taken along line 3--3 of Fig. 1;

'Fig. 4 is a representative portion of a cross section taken along line 44 of Fig. 1;

Fig. 5 is a cross section taken along line 55 of Fig. 2. For completeness of illustration, an ammunition round of the type preferably usable in the gun is shown in firing position within the gun and is shown partly broken away and party in section;

Fig. 6 is an enlargement of a corresponding portion (i. e., the upper left hand portion) of Fig. 5, but showing certain components of the gun and of the ammunition round in different positions, respectively, from the positions shown in Fig. 5;

Fig. 7 is a section taken along line 7-7 of Fig. 2; and,

Fig. 8 is a section taken along line 8-8 of Fig. 7.

CONSTRUCTION OF THE GUN- The gun of the present invention comprises, as basic structural components, a barrel 18 (Figs. 1 and 5) a chamber 19 (Figs. 1 and 4 through 7) and a cap 20 (Figs.

1 through 7). The essential details of the just-named components follow and other components complementary thereto are identified and described as appears necessary.

Barrel 18 has the externally threaded rear or breech end 25 (Figs. 1 and 5) and the bore 46 (Fig. 5).

Chamber 19 has an internally threaded forward or muzzle end 26 (Figs. 1 and 5) and a rear end (Figs. 1 and 4 through 7); the rear end having the external thread .52 (Figs. 1 and 5 through 7"). Internally, chamber 19 has an ammunition opening SS (Figs. 5 through 7) and a tapered face 63. V V

being accommodated by the chambers internally threaded forward end 26 and the chambers ammunition opening being coaxial with the barrels bore 46. p

Also on chamber 19 are a firing mechanism 38 (Figs. 1 and 2) by which the gun is fired and a safety mechanism 39 (Fig. 1) by which accidental operation of the firing mechanism is prevented.

Cap 20 has an internally threaded recess 72 (Figs. 1 and 4 through 7) which extends from that caps forward end 73 (Figs. 1 and 5 through 7) almost to its rear end 74, a-

recess 75 (Figs. 3, 6 and 7) which originates from the floor 76' (Figs. 6 and 7) of recess 72 and extends closer to the caps rear end and atapered opening 77 (Figs. 2 .and 5 through 7) which issues from the floor 78 (Figs. 5

through 7) of recess 75 and extends to the caps rear face.

Cap 20 fits on chamber 19; the caps internally threaded forward end 73 fitting over the chambers externally threaded rear end 50. It is understandable, therefore, that rotation of the cap relative to the chamber will result in the caps movement in a direction along the chambers axis.

In the operation of thegun, cap 20 is rotatable on chamber 19 to either one of two positions through the agency of the handles 88 and 89 (Figs. 1, 2 and 5) on that cap: a closed position shown in Figs. 1 through 5 and 7, in which the cap is at the limit of its travel toward the right with respect to the chambers rear end 50; or an open position shown in Fig. 6, in which the cap is at the limit of its travel toward the left with respect to the chambers rear end 50. More will be said about these positions later, when the operation of the gun is explained.

' Inside cap 20 are a retaining ring (Figs. 5 through 7) a plurality of breech sectors 98 (Figs. 2 through 7) and a plurality of V-shaped springs 115 (Figs. 3, 4 and 6 through 8); the ring being attached to the cap, as by the screws 86 (Fig. 1).

- Ring 85 has a rear face (Figs. 6 and 7) and a cylindrical opening 96, which opening has a tapered portion 97. As also shown in Figs. 6 and 7, ring 85 is accommodated in recess 75 of cap 20 so that a space 87 exists between that recess floor 78 and that rings rear face 95;

Breech sectors 98 are substantially identical to each other. Therefore, a description of one sector will suffice for all sectors. Each sector has a body portion 100 (Figs. 4 through 6 and 8), a flanged, rear end 101 (Figs. 3 and 5 through 7), a stepped-in forward end 102 (Figs. 5 through 7 a tapered shoulder 103 (Figs. 5 through 7 a tapered, arcuate surface 104 (Figs. 2 through 7), a rear face 105 (Figs. 3 and 5 through 7), a forward face 106' (Figs. 6 and 7), a crowned arcuate rim 107 (Figs. 3, 6 and 7), the radially extending faces 110 (Figs. 2 through 4, 6 and 7) and a recess 111 (Figs. 3, 4 and 6 through 8) in each radial face.

Breech sectors 98 are disposed side by side in cap 20, as can be understood from Figs. 2 through 7; the sectors flanged ends 101 being accommodated in the caps recess 75 and the sectors stepped-in ends extending into the caps recess 72.

During operation of the gun, breech sectors 98 are made to assume simultaneously either one of two positions; a closed position shown in Figs. 1 through 5 and 7, or an open position shown in Fig. 6. These positions will be explained later, when the guns operation is described.

V-shaped springs 115 are substantially identical to each other. Therefore, a description of one such spring will sufiice for all springs. Each V-shaped spring has a crotch 116 (Figs. 3, 7 and 8), the legs 117 (Figs. 4 and 6 through 8) and a tab 118 (Figs. 7 and 8) on each leg; the legs tending constantly to spread apart from each other to the position indicated in Fig. 8.

There is one such spring between adjacent sectors 98; each spring being accommodated in the sectors recessed portions 111, as shown in Figs. 3, 4, 6 and 7; and each of the springs tabs 118 being accommodated in a recess 112 (Figs. 6 through 8) formed. in the breech sectors.

OPERATION OF THE GUN In describing the guns operation, the matters of loading, firing and reloading the gun will be explained in succession. However, before such explanation,. it appears necessary, in order to facilitate'a full understanding of the guns operation, to describe briefly the ammunition round 62 (Fig. which is representative of the type preferably, but not exclusively, used in conjunction with the gun of the present application.

As earlier stated herein, such ammunition round is the subject of United States patent application Serial No. 271,056 filed February 11,- 1952, for Recoilless Type Ammunition Having SelfeCont-ained Venturi, .in my name. Therefore, only such details of the ammunition round as seem necessary to supplement the description of the gun appear to be necessary here.

Ammunition round 62 comprises, as basic structural components, a projectile 21 (Fig. 5) and a cartridge case 22.

Projectile 21 has a nose 170 (Fig. 5), a bourrelet 171 and a pre-engraved rotating band 172; such band, of course, not being required, if the projectile is to be fired from a smooth bored gun barrel.

Cartridge case 22 is made up of front, intermediate and rear members 175 (Fig. 5), 176 (Fig. 5) and 177 (Figs. 5 and 6), respectively.

The cartridge cases front member 175 has a neck 173 (Fig. 5), a tubular portion 178 and a tapered shoulder 179; the casesneck being joined releasably, in convenient manner, to the rear end of projectile 21.

The cartridge cases intermediate member 176 is cuplike and has an open end 180 (Fig. 5) and a spherical end 181, which end is closed, except for the radially extending slits 194. Additionally, intermediate member 176 has an electrically insulating bushing 184 which extends. through the intermediate members wall, an electrically insulating ring 136 which encircles the-intermediate member, an electrical contact ring 187 which is imbedded in insulating ring 136, an electricity conducting wire 190 which extends through bushing 134, through ring186 and is connected for conduction of electricity to ring 187, an electrically operable detonator 191 at the other end of wire 19%, and an electricity conducting wire 192 which is connected to detonator 131 and to the intermediate members wall.

As shown'in Fig. '5, the intermediatemembers open end 180 fits into front member 175, those parts being joined together in any convenient manner; and the inter' mediate member and the front member contain a propellant 193. V

The cartridge Jcases rear member 177 has a tubular portion 195 (Figs. 5 and 6) and a venturi portion 196, which portion has'the'throat 1%; the rear member being joined, in convenient manner, to intermediate member 176.

. Loading the gun Before the gun can be loaded, cap 29 and breech sectors 98 must be in the open position shown in Fig. 6; the cap then being at the limit of its travel toward the left with respect to rear end 5:) of chamber 19, the breech sectors being diverged to their fullest extend radially with respect to the chambers axis, and the sectors arcuate surfaces 164 defining an opening large enough to allow for passage of the ammunition round into the gun. Therefore, in describing the loading of the gun, it is assumed that the just-stated conditions prevail.

Thereupon, ammunition round 62 is thrust, projectile 21 .fore'most, axially iuto'the gun, as far'as possible, through the breech caps' taperedopening 77,111:: pre

jectiles rotating band 172 being caused, by well-known means, to register with the rifling in the barrels bore 46, as indicated in Fig. 5; and the ammunition rounds venturi portion 196 abutting the breech caps tapered opening 77, as shown in Fig. 6, which abutment limits, for the time, insertion of the ammunition round into the gun. However, that round is not yet fully inserted and seated r. in firing position in'the gun; such insertion and seating button forming a part of firing mechanism 38.

occurring later, as will be explained, when the cap and the breech sectors are moved to their closed positions.

Then cap 20 is rotated on chamber 19 to the closed position shown in Figs. 1, 5 and 7. During such rotation, the cap travels axially toward the chambers rear end 50. As this happens, the caps annular shoulder 78 abuts the breech sectors faces so that those sectors are pushed toward the chambers rear end. In due time, the sectors forward ends 1612 move against the chambers tapered face 63. Consequently, the sectors are simultaneously converged toward the ammunition rounds venturi 196 to their closed position against the resistance of V-shaped springs 115. As the sectors are so converged, their arcuate surfaces 104 abut the ammunition rounds venturi 196 so that the ammunition round is fully inserted and seated, ready for firing, in the chambers ammunition opening 55, as shown in Fig. 5; the cartridge cases shoulder 179 abutting and being supported by a similar shoulder in ammunition opening 55, the cases. tubular portions 178 and also abutting and being supported by another part of the ammunition opening, and the breech sectors abutting and supporting the car tridge cases venturi 196, which venturi acts as a liner for the breech sectors.

In other words, when breech cap 2% and breech sectors 98 in their fully closed position (Fig. 5), practically the entire circumferential surface of the ammunition rounds cartridge case 22 is firmly supported by the guns barrel 18, chamber 19, breech sectors 9 3 and tapered opening 77, collectively. Furthermore, the guns sectors 98 are in position to act as a breech block to prevent'rearward displacement of the cartridge case-when the gun is later fired; the sectors stepped-in ends 102 fit.ing inside ammunition chamber 55, the sectors tapered shoulders 1tl3 abutting the chambers face 63, the sec tors flanged ends 16-1 being accommodated in the caps recess '75, and the sectors faces 105 being in the abut ment withthe caps shoulder '78.

Firing the gun To enable the gun to be fired, safety mechanism 39 (Fig. 1) is moved manually to its firing position (not shown) through the agency of a button 152 which forms part of that mechanism. 3

Then a trigger button 144 (Fig. 1) is depressed; this Such action moves a firing pin (not shown) in the gun into contact with the ammunition rounds contact ring 187 and, in so doing, closes an electrical circuit (not shown) through the rounds detonator 191. whereupon, that detonator, then propellant 193 are ignited.

Gas pressure generated in consequence of the ignition of propellant 193 shoots projectile 21 from the gun and blows open spherical end 181 of the cartridge cases in termediate member 176 along slits 194. Then'rnost of that gas, which is very hot and usually highly corrosive To reload the gun, cap 24) is rotated to the open position, shown :in Fig. 6, through the agency of handles 88 and 89. During such rotation, the cap travels axially Men-Ankh.

away from the chambers rear end 50. As this happens, safety mechanism 39 is automatically restored to its safe position, cartridge case 22 remaining in the gun from the previously fired ammunition round is partially ex tracted from ammunition opening 55 because of the abutment between the caps tapered opening 77 and the cartridge cases venturi portion 196, and face 95 of retaining ring 85 in the cap abuts the sectors faces 106 so that those sectors are moved away from the chambers rear end. When the sectors ends 102 are clear of the chambers ammunition opening 55, the sectors are simultaneously diverged radially away from the cartridge cases venturi 196 to their fully open position by V shaped springs 115. Then the cartridge case is fully extracted from the gun by hand, another round is inserted into said chamber, the combination therewith of: a plurality of breech sectors disposed at the rear end of the chamber the gun, as explained earlier herein, and cap is rotated to the closed position, as also explained earlier herein.

SUMMARY concentrically with respect to that chamber and defining a venturi opening, said sectors being simultaneously divergable radially with respect to the chamber; means for supporting said sectors with respect to the chamber; and means for simultaneously moving said sectors radially with respect to the chamber to provide for passage of the ammunition and for securing that round in the chamber.

2. The combination defined in claim 1 plus resilient means disposed between adjacent breech sectors, said means tending constantly to diverge the breech sectors radially away from the chambers axis simultaneously.

3. The combination defined in claim 2 wherein the resilient meansis a plurality of V shaped springs, one of said springs being disposed between adjacent breech sectors.

References Cited in the file of this patent UNITED STATES PATENTS 1,108,717 Davis Aug. 25, 1914 1,450,558 Maze et al. Apr. 3, 1923 2,454,276 Davis Nov. 23, 1948 2,492,279 Fowler Dec. 27, 1949 

